The present protocol will continue to study the ocular hypotensive properties of systemic and topical cannabinoids in clinical trials using glaucoma patients. Significant ocular and systemic hypotensive effects have been demonstrated in heterogenous and in open angle glaucomas after smoked marijuana and oral delta 9 tetrahydrocannabinol (delat 9 THC) capsules, but not after low-dose topical delta 9 THC therapies. Hypertensive glaucoma subjects are particularly sensitive to all forms of cannabinoids as greater decreases in systolic blood pressure and ocular tension have been documented in those glaucoma subjects with concomitant essential hypertension. Further study will therefore included: (1) Randomized, double-masked trials with topical cannabinoids with delta 9 THC, delta 8 THC and cannabidiol, a non-cardiac active cannabinoid. These substances will be prepared in both light mineral oil and aqueous-based vehicles as these delivery forms closely approximate present glaucoma therapies (eyedrops), (2) systemically administered cannabinoids (smoked marijuana or oral capsules for non-smokers) will be tried in glaucoma subjects refractive to standard glaucoma medications in an attempt to avoid surgical interventions and (3) laboratory animals (conscious dogs) will provide the model by which cannabinoids' effect on aqueous dynamics are monitored. Blood pressure, tonometry and tonography are objectives studies of aqueous dynamics which we have accurately performed in conscious dogs.